Well, I have a variety of NOID daylilies. Currently I have about 150-200 growing in my yard. What I see happen is that some grow well here and some don't and disappear after the 2nd year. All mine are grown from seed (which I have received from generous folks who shared with me from their own gardens around the country). I do my own hand-pollinating of the ones that survive and make more that way. I think some cultivars of daylilies are bred for northern places that have cold winters. But I would imagine that the majority of daylilies will grow in the south without too much of a problem. I am further south on the east coast of central FL.
Dan - What kind of soil medium are you growing them in? Michele grows hers in a very good mix. (Much better than what I grow mine in!) I amend any place I plant daylilies with pine fines, compost, and some good topsoil. I also mulch with pine fines. Michele shared with us her use of Alfalfa pellets to feed the earthworms and her plants. I have since tried that and have already seen results! I highly recommend you try Michele's method. They also need to be watered regularly during the growing season. Another possibility ... the crowns may be buried too deep. If so, they won't bloom and may perish eventually because of that. A lot of factors that could be causing your dilemma.
